Thermic siphon



June 1' 3. G. CHRISTENSYON T'HERMIC SIPHON 2 Sheets-Sheet 1 Filed July 8, 1955 June 9, W3. 6. .1 CHRIS/PERSON THERMIC SIPHON Filed July 8, 1955 2 SheetsSheet 2.

Patented June 9, 1936 PATENT OFFICE THERIVHC ,SIPHON Gust J. Ohristenson, Chicago, Ill., assignor to Locomotive Firebox Company, Chicago, 111., a corporation of Delaware .6 Glaims.

This invention relates to improvements in thermic siphons and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

One of the objectsof the present invention is to provide a thennic siphon, .ior use in connection with a firebox oi. the combustion chamber type and which shall not only have greaterfiexibility but which shall also be formed in such manner as to cooperate with a fire wall in the combustion chamber and with a rearwardly extending arch in increasing the combustion-emciency of the firebox as well as increasing the water steaming and circulating action of the boiler.

A further object of the invention is to provide a thermic siphon with a plurality of inlet necks certain of which open through the bottom of the combustion chamber and with which there is associated an upright firewall arranged in the combustion chamber, the said .necks and portions of the body of the siphon providing the supports for the bricks of a fire arch that extends rearwardly and upwardly from said wall. still a further object of the invention is to provide a siphon of this kind having inlet necks associated with the front and rear ends of the siphon body, the necks each having a curve therein of. substantial radius whereby they may move to accommodate the movement of the siphon during expansion and contraction of the firebox sheets in response to temperature changes.

The above mentioned objects of the invention, as well as others, together with the many advantages thereof will more fully appear as I proceed with my specification.

In the drawings:

Fig. 1 is a longitudinal vertical sectional view through a locomotive firebox of the combustion chamber type embodying the preferred form of siphon, and firewall and .arch arrangement;

Fig. 2 is a transverse vertical sectional view through the same as taken on the line 2-2 of Fi I Fig. 3 is a detail vertical sectional view on an enlarged scale, through a part of the structure shown in Fig. 1 as taken on the line 3-3 of said Fig. 1, and

Fig. 4 is a view similar to Fig, l and illustrates more particularly a modified form of construction of inlet neck arangement for the rear end of the siphon body.

Referring now in detail to that embodiment of the invention illustrated in Figs. 1 to 3 inclusive of the accompanying drawings, the firebox therein shown includes the crown sheet 5 which merges Application July a, 1935, Serial No. 30,289

into the inner side sheets 6,,the inner back sheet .I and inner throat sheet 8. The crown sheet extends forwardly of the inner throat sheet v8 to form the top of the combustion chamber 9. This chamber is closed at the front end by a fiue sheet Ill and the bottom I I of saidchamber joins the front end of the inner throat sheet 8.

The outer back sheet is indicated at E2; the outer side sheets are indicated at l3 and the outer throat sheet is indicated at I l. Said sheets 00- .operate with the top sheet and outer side sheets 13 in forming the back water leg Hi, the side water legs l6 and the front throat I! respectively, all in communication with the water space [8 of the boiler. The back and side water legs and the front throat are bottomed by a mud. ring [9 and portions of the inner and outer back sheets are formed to coact in providing a fuel door opening 20. l V

In the firebox is a plurality of the improved siphons, each indicated, as a, whole, as at 2|. .As shown herein, there are three of. such siphons, with one disposed upon the'median line of the firebox and with the other two, spaced one at each side of the first mentioned siphon as shown in Fig. 2.

Each siphon, as herein shown, comprises a fiat hollow body formed to provide relatively deep front and rear end compartments 22--23 respectively, separated by an intermediate compartment 24 of a more shallow depth. Each body ineludes laterally spaced side walls 25-25 and transversely rounded front and rear end walls 25 and 21 respectively. Said side and end walls are flared outwardly around the entire top end of the body, by means of inside curved corners 28 to merge into a laterally extending flange 28a. This flange is fitted and welded as at 29 in a suitable longitudinal opening in the crown sheet. Thus the open top end of the body provides a common discharge for all three compartments of the siphon body, into the water space of the boiler above the crown sheet.

, The front wall 26 of the body is disposed at a relatively steep angle extending downward and forwardly from the crown sheet. The rear wall 2'! of the body is disposed at substantially the same angle to merge into a rounded corner or .nose 21a. That part of the body defining the rear compartment 23 terminates in a stub-like tubular extension 3!.

Associated with said rear compartment of the siphon body is a downwardly and forwardly extending inlet neck 32 of substantial length. As shownherein said neck is made from a piece of seamless tubing and front end of the neck is anchored in a flexible diaphragm 33 preferably flanged up from the top portion of the throat sheet 8. The rear end of said neck is butt welded to the end of the body extension above mentioned as indicated at 34.

The bottom of the front compartment 22 is formed by a rounded and bulged portion 35 disposed above and arranged at a lesser inclination than that of the neck 32. This bulged bottom along with the parts of the side and front end walls of the siphon body are formed to provide a stub-like tubular extension 36 for the front compartment of the body. Said extension or neck receives one end of an inlet tube 31, which extends as a continuation of said neck and is then curved downwardly to be secured in a suitable diaphragm-like opening in the bottom I I of the combustion chamber so as to open into the water space of the boiler at this point. The inlet tube 31 is also preferably made of seamless tubing of a diameter substantially the same as that of the neck 32.

The bottom of the intermediate compartment 24 is formed by the top portion or part 38 of a substantially circular formation. Another portion of said formation merges into a rounded corner 39 for the front compartment and said corner blends into the bulged bottom 35 of said compartment. A third portion of said substantially circular formation forms the front end for the rear compartment and merges into the top of the stub-like extension 3|.

Preferably the entire siphon body and the tubular extensions 3l-36 therefor, are made from an integral sheet, cut to such shape that when folded upon itself, by means of a suitable form block, it produces the body and extensions shown. Such an integral structure will have a line of weld extending the length of the front wall, along the bottom of the front compartment, around the substantially circular formation 38 and down along the top of extension 3|. Also, a line of welding will follow down along the rear wall 21 to merge into the corner 21a, said line of welding being necessitated because of the removal of certain excess metal from the sheet, that permits the making of the inclined rear wall of the body without a puckering or buckling at said corner. To brace the body of the siphon against internal pressures, the same is transversely staybolted as at 40. Due to the outline shape of the body, less staybolts are required than in a conventional siphon body and this without sacrificing the safety factor.

Instead of making the entire body and the main inlet neck from a single sheet of metal, that part of the body comprising the front compartment may be made from a single sheet of metal and that part of the body comprising the rear compartment and the main inlet neck may be made from a single sheet of metal and the two parts joined by butt welding at about the middle of the intermediate compartment 24. While a two part body requires more welding operations, it has certain advantages in the economy in plate material, due to the use of smaller sheets and to the manner in which the grain of the metal in the two sheets thus used, may be disposed. Whichever way the siphon is fabricated, that is, either from one or two sheets of metal, the operation of the siphon is the same and the advantages gained over the conventional siphons are likewise the same.

In either instance, the arrangement of the parts is such that the relatively long neck is under compression when in a cold condition as when there is no fire in the fiirebox. Such compression, of course, is in relation to the body of the siphon and substantially equals the amount of the movement due to expansion, as when the firebox is being fired under service conditions. Under such conditions, when the siphon is under service heat and pressure, only slight stresses, incapable of starting fracture at the inside corners previously mentioned are present because the force of the expansion will return the neck and the upper part of the siphon to their normal positions and thus neutralize the movement thereof.

In the combustion chamber an upright transverse fire wall 4! is provided of a height approximating about half of the vertical dimension of the combustion chamber. This wall is made of refractory brick and the front face thereof is pref erably arranged slightly to the rear of the neck tube 31 where it enters the bottom of the combustion chamber, portions of all of the necks passing through said wall. Associated with said wall and extending rearwardly therefrom is an arch 42 made up of the usual brick and which arch terminates at its rear end at a point spaced rearwardly from the front wall of the siphons. The brick forming that portion of the arch between the intermediate and side siphons are supported at their sides upon portions of the inlet tubes 31 and portions of the bulge 35 of the respective siphon bodies. The brick of the arch between the side siphons and the inside sheets of the firebox, engage at one side upon the necks 31 and siphon body bulge 35 and engage at the other side against the said sheets as best shown in Fig. 2. It is to be understood that by reason of the engagement of the frontmost brick of the arch against the firewall, the brick of the arch are prevented from sliding forward as they otherwise would, because of the inclination of the siphon parts upon which the brick engage.

When the siphons are installed in a firebox having a so-called long combustion chamber, it may be advisable to provide therein, forward of the firewall, a fourth siphon 43 of a generally Y shaped formation as appears in Fig. 1. Such a siphon includes a fiat hollow staybolted body 44 disposed in the longitudinal median plane of the firebox, the body tapering downwardly at its front and rear to merge into a tubular inlet neck 45. The top end of the siphon 43 opens through the top sheet portion of the combustion chamber and the neck opens through the bottom sheet portion of the combustion chamber.

In Fig. 4 of the drawings, is illustrated a slightly modified form of the structure associated more particularly with the rear end of the siphon. In this respect, the siphon body may be said to have only a single compartment, and the rear end of the body terminates in a short, downward neck extension 3|a. The inlet tube for the rear end of the body is indicated at 32a and the rear end of said neck is formed as an upward curve or elbow 32b which is butt welded to the bottom of the neck extension 3Ia. This construction simplifies the manufacture of the siphon body and permits the use of a longer neck tube. This increased length, of course, has its advantages in the greater flexibility afforded thereby. In Fig. 4, the same firewall and arch structure shown in Fig. 1 is present.

By reason of the structure described, an efficient arch structure is afforded for use in a siphon-equipped firebox of the long combustion chamber type. The arch in connection with the firewall, causes a reversal of the products of combustion so that their action on the siphon bodies, so far as steaming is concerned, is increased. Again, the structure while it provides a relatively long arch, the front end does not so closely approach the crown sheet as to restrict the area of the flame passageway above the arch. Thus blast action with its highly erosive wear is reduced. Again the front end of the arch may be brought into such an elevation above the fuel door opening as to make substantially impossible, the throwing of'fuel upon the top of the arch when the firebox is hand fired.

While in describing the invention, I have referred in detail to the form, arrangement and construction of the various parts thereof, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

1 I claim as my invention:

1. In a locomotive boiler firebox having a combustion chamber, a hollow water steaming and circulating wall including a flat hollow body opening at thetop through the crown sheet of the firebox, an inlet neck for the rear end of said body and opening through a part of the firebox into the boiler water space of the boiler, a second inlet neck for the front end of the body and opening through the bottom of the com- 7 bustion chamber, an upright fire wall in and extending transversely of the combustion chamber, and an arch supported at least in part by said body and the second mentioned inlet neck respectively and extending rearwardly from the fire wall.

2. In a locomotive boiler firebox having a combustion chamber, a hollow water steaming and circulating wall including a flat hollow body opening at the top through the crown sheet of the firebox, an inlet neck for the rear end of said body and opening through a part of the firebox into the boiler water space of the boiler, a second inlet neck for the front end of the body and opening through the bottom of the combustion chamber, an upright fire wall in and extending transversely of the combustion chamber, an arch supported at least in part by said body and the second mentioned inlet neck respectively and extending rearwardly from the fire wall, and a second hollow water steaming and circulating member in said combustion chamber forward of the fire wall and opening at its ends through the top and bottom of the combustion chamber.

posed at elevations lower than that of a certain other of said compartments, a plurality of tubular inlet necks for said wall, each communicating at one end with the bottom of said certain ones of said compartments, the other end of one of said necks opening through a part of the firebox into the water space of the boiler, the other end of the other inlet neck opening through the bottom of the combustion chamber, an upright fire wall in said combustion chamber and an posed at elevations lower than that of a certain other of said compartments, a plurality of tubular inlet necks for said wall, each communicating at one end with the bottom of said certain ones of said compartments, the other end of one of said necks opening through a part of the firebox into the water space of the boiler, the other end of the other inlet neck opening through the bottom of the combustion chamber, an upright fire wall in said combustion chamber and an arch supported at least in part by said other of said inlet necks and by parts of said body respectively, and a second hollow water steaming and circulating member in said combustion chamber forward of said wall and opening at its ends through the top and bottom of the combustion chamber.

5. In a locomotive boiler firebox, a hollow water steaming and circulating wall in said firebox including a body opening through the crown sheet of the firebox, an inlet neck communicating at one end with the front portion of the body and opening at its other end through a part of the firebox to communicate with the water space of the boiler, and means providing a relatively long inlet neck for the rear end of said body and connected at its front bottom end with the front throat of the firebox and having an upwardly curved rear end connected to said rear end of the body.

6. In a locomotive boiler firebox, a hollow water steaming and circulating wall in said firebox including a body opening through the crown sheet of the firebox, an inlet neck communicating at one end with the front portion of the body and opening at its other end through a part of the firebox to communicate with the water space of the boiler, and a seamless tube connected at its front end with the front throat of the firebox and having an upwardly curved rear end connected to the rear end of the body.

GUST J. CHRIS'I'ENSON. 

